Okay I've never dyed my hair so this might not be too helpful to you

but recently, I've been using Dove's Intense Moisturizing shampoo and holy crap, that stuff is godly. I seriously love it. You know how the first time you use a shampoo, it makes your hair all nice - then it kinda dies off? This shampoo hasn't. It really has tons of moisturizers so maybe that would help you.
Oh, I checked the site. It has one special for color-treated hair called Moisture Rich Color Shampoo. Maybe that'd work
